The present invention relates to an exposure system incorporated in an image recording apparatus for recording and reproducing an image of an original. The exposure system exposes a photosensitive recording medium to light representing the image of the original.
Conventional exposure systems in such an image recording apparatus includes a light source for exposing an original to light and a photosensitive recording medium for sensing light reflected from the original. The light source and the photosensitive recording medium are disposed below an original table or holder which supports the original thereon. The exposure system also includes an optional exposure unit disposed above the original holder. The exposure system is selectively operable as a reflection-type exposure system and a transmission-type exposure system. When operating as the reflection-type exposure system, the photosensitive recording medium is exposed to light reflected from the original. When used as the transmission-type exposure system, light emitted from the optional exposure unit is transmitted through the original and applied to the photosensitive recording medium. Since the optional exposure unit is disposed above the original holder, it is necessary that an installation space be provided above the original holder for accommodating the optional exposure unit therein. Therefore, the entire exposure system is large in size as the optional exposure unit and the light source are respectively located above and below the original holder.
In another type of the exposure system, a light source unit housing a light source is fixedly installed above an original holder in a position confronting a central area, or rightmost or leftmost portion, of the original holder for downardly irradiating light onto an original supported on the original holder. Where the light source unit is fixedly positioned above the original holder in confronting relation to the central area of the original holder, an optional exposure unit cannot be installed above the original holder because of the presence of the fixed light source unit.